Apple’s iPad has been hyped as the future of publishing — books, magazines, you name it. Now high-profile venture firm Kleiner Perkins Caufield & Byers is putting millions of dollars behind that idea. Through its iPhone- and iPad-focused iFund, Kleiner just led a $6 million round in iPad app publisher Callaway Digital Arts.

Is Kleiner Perkins Caufield & Byers’ social push coming too late? The venture firm just announced the creation of a $250 million sFund for investing in “social Web” startups, but 2010 seems like the wrong time to be jumping onto that bandwagon.

Neil Young, chief executive of iPhone game maker Ngmoco, said in an interview today that he agreed to sell his company to Japan’s DeNA for $400 million because of a shared vision to build the world’s top social mobile gaming company. DeNA announced the acquisition earlier today.

Most of the focus at venture firm Kleiner Perkins Caufield & Byers’ iFund event today was on Apple’s upcoming iPad, with five startups (Gogii, Ngmoco, Pinger, Shazam, and Booyah) confirming on-stage that they’re developing iPad applications. Kleiner partner John Doerr sounded especially excited about the device, claiming that it will “rule the world.”